Significant strides in the miniaturisation of quantum systems are being made by rapid advances in the development of compact lasers; however, there remain some substantial challenges where higher powers, short wavelengths, high spectral purity, or operation in harsh/remote environments are required.  This is particularly critical for deployable quantum systems for position, navigation and timing (PNT).  In this project we will address this key laser performance gap via the development of hybrid monolithic lasers with ultra-low frequency noise at novel wavelengths.  We will build directly on our recent advances in the development of compact lasers for strontium cooling.  In a proof-of-principle, using off-the-shelf optics in combination with our custom semiconductor gain structures, we have recently demonstrated frequency stability of a free-running laser down to 10-12 over 1 s [1,2]. We will now target further step changes in miniaturisation, stability, power scaling, spectral coverage, and electronic control by incorporating the optimal materials (including nonlinear and electro-optic elements) within custom monolithic resonator architectures.  By collaborating with Fraunhofer CAP we will also be able to realise novel resonators via ultra-precision machining (5-axis CNC, newly installed at Fraunhofer CAP) and contact bonding of heterogeneous media, aiming to achieve sub-kHz integrated linewidth from a wavelength-engineerable monolithic laser with electronic control.

1. Martin Lee, Paulo H. Moriya, and Jennifer E. Hastie, “Monolithic VECSEL for stable kHz linewidth,” Optics Express 31 (23), 38786-38797 (2023) 
2. Paulo H. Moriya, Martin Lee, and Jennifer E. Hastie, “Sub-kHz linewidth free-running monolithic cavity VECSEL with 10-12 stability,” Applied Physics Letters 125, 021101 (2024)

In this PhD project we will design, develop, and apply novel hybrid laser systems with ultra-low frequency noise, as required for cold-atom-based quantum systems.  This project will include, but is not limited to:

• optical system design
• laser cavity engineering, including electronic control
• modelling and characterisation of thermal and mechanical noise
• characterisation of laser dynamics including intensity, frequency, and phase noise
• development of novel active and passive stabilisation techniques
• laser spectroscopy
• cold atom experiment design

You will also have the opportunity to work in the laboratories of Fraunhofer CAP during a 3-month placement.

Further information

The Institute of Photonics (IoP), part of the Department of Physics, is a centre of excellence in applications-oriented research at the University of Strathclyde.  The Institute’s key objective is to bridge the gap between academic research and industrial applications and development in the area of photonics. The IoP is located in the £100M Technology and Innovation Centre on Strathclyde’s Glasgow city centre campus, at the heart of Glasgow’s Innovation District, where it is co-located with the UK’s first Fraunhofer Research Centre.

Researchers at the IoP are active in a broad range of photonics fields under the areas of Photonic Devices, Advanced Lasers and Neurophotonics.

Strathclyde Physics is a member of SUPA, the Scottish Universities Physics Alliance.